1. Field of the Invention
This invention generally relates to conveyors, and more particularly relates to cantilevered conveyors capable of transporting concrete and the like over a long span.
2. Description of Related Art
Cantilevered conveyors mounted on self-propelled vehicles for transporting concrete and the like have been known in the past and are described in U.S. Pat. Nos. 3,675,762; 4,624,357; and Re. 29,110. A system for using a single belt with multiple cantilevered conveyors is disclosed in U.S. Pat. No. 3,945,484.
Although self-propelled cantilevered conveyors have been made in the past, they have been subject to design deficiencies which have limited their overall usefulness for many applications. For example, prior arrangements of cantilevered conveyors on a self-propelled vehicle have precluded maximum extension and free rotation of the cantilevered conveyors when used in combination with a feeder conveyor that supplies concrete to the cantilevered conveyors through a swivel transfer unit. Prior cantilevered conveyors also have been limited to a relatively short span due to the inadequacies of the force balancing characteristics of the frames supporting the conveyors. In addition, prior conveyor suspension systems have provided inadequate control of conveyor movement over long spans. The prior art techniques also have failed to properly control the extension and retraction of conveyors to enable concrete to be accurately poured over long spans.
Accordingly, it is a principal object of the present invention to optimize the placement of a cantilevered conveyor on a vehicle so that the conveyor can be rotated through a wide area and elevated to various angles while continuously being provided with concrete or the like from a stationary feeder conveyor operating through a swivel transfer unit.
Another object of the invention is to provide a force balancing frame that enables a cantilevered conveyor to transport concrete over long spans.
Yet another object of the present invention is to provide an improved means of suspending telescoping conveyors so that the movement of the conveyors is easily controlled even when the conveyors are elevated to high angles.
Still another object of the present invention is to provide an improved drive arrangement for simultaneously moving sections of a cantilevered conveyor with improved accuracy and safety.